Vehicle start-up permission device and identification code registering method

ABSTRACT

A vehicle start-up permission device in which an identification code stored in an electronic key can be kept secret. A start-up permission ECU (1) is magnetically coupled with a transmit-receive controlling circuit (6) of an electronic key (3) via an antenna (2) and an antenna (5) of the electronic key (3) with the electronic key (3) being inserted in an ignition key (4) so as to supply electric power for the circuit. When the ignition switch (4) is operated to an ACC position, the start-up permission ECU (1) transmits a random number code. When the transmit-receive controlling circuit (6) of the electronic key (3) receives the random number code, it converts by predetermined encryption processing a previously registered key code to a return code on the basis of the random number code and returns the return code. When the start-up permission ECU (1) receives the return code, it decodes a key code on the basis of the random number code, and when the key code coincides with the previously registered key code, the start-up permission ECU (1) outputs a start-up permission signal to an engine-controlling ECU (7).

TECHNICAL FIELD

The present invention relates to a vehicle start-up permission devicewhich permits the start-up of an engine when an identification code readfrom a transmitter-receiver coincides with a previously setidentification code and to an identification code registering method inwhich a transmitter-receiver code for specifying thetransmitter-receiver and a vehicle code for specifying a vehicle areregistered, as identification codes, in the transmitter-receiver and thevehicle start-up permission device, respectively.

BACKGROUND OF THE INVENTION

In order to improve security, it has been recently suggested that, in avehicle, an electronic key be used in which, for example, a transmittingcircuit is integrated with a mechanical key. In this structure, anidentification code is transmitted from an electronic key in a state ofbeing inserted in an ignition switch, and when the identification codetransmitted from the electronic key coincides with a previously setidentification code, the electronic key is judged to be true and, basedon this, an engine is caused to start up in accordance with a turningoperation of the electronic key.

However, in the above-described conventional structure, theidentification code itself is transmitted from the electronic key, andtherefore, it is possible to read the identification code stored in theelectronic key.

SUMMARY OF THE INVENTION

The present invention has been achieved in view of the above-describedcircumstances and an object thereof is to provide a vehicle start-uppermission device in which an identification code stored in atransmitter-receiver can be also kept secret, and to provide anidentification code registering method in which respectiveidentification codes stored in the transmitter-receiver and in thevehicle start-up permission device are kept secret and are registeredboth in the transmitter-receiver and in the vehicle start-up permissiondevice.

The present invention is an identification code registering method inwhich a vehicle code for specifying a vehicle and a transmitter-receivercode for specifying a transmitter-receiver are respectively registeredin the transmitter-receiver and in a vehicle start-up permission devicewhich permits start-up of an engine when an identification code readfrom the transmitter-receiver coincides with a previously registeredidentification code, the method comprising the steps of: (A) registeringthe transmitter-receiver code and the vehicle code in thetransmitter-receiver and the vehicle start-up permission device,respectively; (B) transmitting a random number code prepared on thebasis of a predetermined procedure in the vehicle start-up permissiondevice, converting by predetermined encryption processing thetransmitter-receiver code to a return code on the basis of the randomnumber code received by the transmitter-receiver to transmit the returncode, restoring the return code received by the vehicle start-uppermission device to the transmitter-receiver code on the basis of thetransmitted random number code, and registering the transmitter-receivercode in the vehicle start-up permission device; and (C) in the vehiclestart-up permission device, converting by predetermined encryptionprocessing the vehicle code to a random number vehicle code on the basisof the random number code and transmitting the random number vehiclecode, restoring the random number vehicle code received by thetransmitter-receiver to the vehicle code on the basis of the randomnumber code, and registering the vehicle code in thetransmitter-receiver.

In accordance with the present invention, the identification codes arerespectively registered in the transmitter-receiver and the vehiclestart-up permission device, which codes being provided to specify thetransmitter-receiver and the vehicle start-up permission device, andthereafter, the vehicle code and the transmitter-receiver code can beregistered in the transmitter and the vehicle start-up permissiondevice, respectively. For this reason, it becomes unnecessary to managethe vehicle start-up permission device and the transmitter-receiver inan integrated manner until these codes are registered. Further, sincethe random number code, the return code, and the random number vehiclecode are transmitted to be registered and the identification code itselfis not transmitted, the identification code can be kept secret.Meanwhile, in this case, step (C) may be executed prior to step (B).

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram which shows an overall structure in afirst embodiment of the present invention.

FIG. 2 is a functional block diagram which shows a start-up permissionECU.

FIG. 3 is a functional block diagram which shows a transmit-receivecontrolling circuit of an electronic key.

FIG. 4 is a diagrammatic view which shows overall structure andoperation.

FIG. 5 is a flowchart which shows the operation of a start-up permissionECU.

FIG. 6 is a flowchart which shows the operation of a transmit-receivecontrolling circuit of the electronic key.

FIG. 7 is a flowchart which shows a subroutine of step S20 shown in FIG.5.

FIG. 8 is a flowchart which shows a subroutine of step T10 shown in FIG.6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the attached drawings, the present invention will behereinafter described in detail.

FIG. 1 schematically shows an overall structure. In this figure, astart-up permission ECU (Electronic Control Unit) 1, which serves asstart-up permission means, random number code transmitting means, andidentification code transmitting means, includes a coil 2 and iselectromagnetically coupled via the coil 2 with an electronic key 3serving as a transmitter-receiver.

In other words, the coil 2 is disposed in such a manner as to correspondto an ignition switch 4, and with the electronic key 3 inserted in theignition switch 4, the coil 2 is electromagnetically coupled with a coil5 of the electronic key 3 so as to supply electric power for atransmit-receive controlling circuit 6 and an identification code isread from the transmit-receive controlling circuit 6.

Here, when the start-up permission ECU 1 receives an ACC signal (i.e., asignal which indicates that the switch is operated at an ACC position),the start-up permission ECU 1 communicates with the transmit-receivecontrolling circuit 6 of the electronic key 3. When the electronic key 3is judged to be true, the start-up permission ECU 1 outputs a start-uppermission signal to an engine-controlling ECU 7.

The engine-controlling ECU 7 receives an ON signal from the ignitionswitch 4 (i.e., a signal which indicates that the switch is operated atan ON position) and a START signal from the ignition switch 4 (i.e., asignal which indicates that the switch is operated at a START position)in a state in which the start-up permission signal is input to theengine-controlling ECU 7, and when the engine-controlling ECU 7 acceptsthe START signal, it is provided to start up an engine by driving astarter of the engine.

FIG. 2 is a functional block diagram of the start-up permission ECU 1.In this figure, when the electronic key 3 inserted in the ignitionswitch 4 is operated at the ACC position, a random number codegenerating circuit 8 generates random numbers and the random numbers arestored in a random number code holding register 9. A modulation circuit10 modulates the random number code stored in the random number codeholding register 9 by an oscillating frequency of an oscillating circuit11 to a transmission signal and outputs the modulated signal to anoutput circuit 12. The output circuit 12 transmits the transmissionsignal from the modulation circuit 10 via the coil 2.

When it is determined by a receiving circuit 13 that the electronic key3 is inserted in the ignition switch 4, on the basis of a signalreceived via the antenna 2, the receiving circuit 13 sends aninstruction to a power source control circuit 14. When the power sourcecontrol circuit 14 receives the instruction from the receiving circuit13, it outputs power source voltage from a battery 15 to each of thecircuits which form the start-up permission ECU 1 with the power sourcevoltage being stabilized at a control power source voltage.

Further, the receiving circuit 13 outputs the signal received from thecoil 2 in such a manner that the signal is subjected to waveform shapingprocessing through a waveform shaping circuit 16. A synchronous circuit17 separates a synchronous signal included in the received signal fromthe waveform shaping circuit 16. A clock circuit 18 outputs a clocksignal in accordance with the synchronous signal of the synchronouscircuit 17. A code restoring circuit 19 restores (decodes) a randomnumber code and a key code by inputting the received signal from thewaveform shaping circuit 16 synchronously with the clock signal from theclock circuit 18. In this case, the random number code and the key codecan be restored in such a manner that a predetermined calculation iseffected for the received signal on the basis of a vehicle code.Meanwhile, the code restoring circuit 19 includes a φ_(S) determinationcircuit, not shown, for making a determination for φ_(S), whichindicates that a vehicle code, S, (which will be described later) isblank (i.e., vehicle code S is not registered in a nonvolatile memory ofthe electronic key 3).

A code determination circuit 20 is formed from a random number codeshift register 21 and a key code shift register 22 and determineswhether the random number code and key code received from the coderestoring circuit 19 is true or not.

Namely, the random number code shift register 21 stores the randomnumber code transmitted from the code restoring circuit 19 by a shiftoperation. Further, the key code shift register 22 stores the key codetransmitted from the code restoring circuit 19 by shift operation. Arandom number code collating circuit 23 compares the random number codestored in the random number code shift register 21 and the random numbercode stored in the random number code holding register 9. Further, a keycode collating circuit 24 compares a key code stored in a key code shiftregister 22 and a key code previously registered in a nonvolatilememory. In this case, when it is determined by the random number codecollating circuit 23 that both random number codes coincide with eachother, it is possible to determine that communication between theelectronic key 3 and the start-up permission ECU 1 was made normally.Accordingly, when the communication between the electronic key 3 and thestart-up permission ECU 1 is made normally and it is determined by thekey code collating circuit 24 that both key codes coincide with eachother, it is possible to determine that the proper electronic key 3 isused. When the random number code and the key code coincide with eachother as described above, the code determination circuit 20 outputs astart-up permission signal to the engine-controlling ECU 7.

Further, the key code collating circuit 24 includes a flag determinationcircuit, not shown, for determining whether a flag of key code K,described later, is set up and a write circuit, not shown, for writingthe key code K into a nonvolatile memory of the start-up permissionECU 1. The key code collating circuit 24 is connected to the coderestoring circuit 19. In addition, a P calculation circuit 40, describedlater, is provided in the start-up permission ECU 1 and the Pcalculation circuit 40 is connected to the above-described coderestoring circuit 19 and also to the modulation circuit 10.

Meanwhile, although in FIG. 2 the start-up permission ECU 1 is shown ina functional block diagram, the start-up permission ECU 1 is mainlyformed of a microcomputer.

FIG. 3 shows the transmit-receive controlling circuit 6 of theelectronic key 3 in a functional block diagram. In this figure, anelectric power receiving circuit 25 stabilizes electric power receivedby a receiving antenna 5 at a predetermined control power source voltageand outputs the same. A signal receiving circuit 26 outputs the signalreceived by the receiving antenna 5 in such a manner that the receivedsignal is set in a state of being shaped by the waveform shaping circuit27. A synchronous circuit 28 separates a synchronous signal included inthe received signal from the waveform shaping circuit 27. A clockcircuit 29 outputs a clock signal in accordance with the synchronoussignal of the synchronous circuit 28.

A random number code shift register 30 stores, by a shift operation, arandom number code included in the received signal from the waveformshaping circuit 27 in accordance with the clock signal from the clockcircuit 29. A key code shift register 30 stores a key code stored in anonvolatile memory by a shift operation. A vehicle code shift register32 stores a vehicle code stored in a nonvolatile memory by a shiftoperation.

A code generating circuit 33 generates a return code by predeterminedencryption processing on the basis of the respective codes stored in therandom number code shift register 30, the key code shift register 31,and the vehicle code shift register 32.

A modulating circuit 34 modulates a modulation code from the codegenerating circuit 33 by an oscillating frequency from an oscillatingcircuit 35 to generate a return code. An output circuit 36 transmits thereturn code from the modulation circuit 34 through the antenna 5.

Further, the electronic key 3 is provided with a vehicle codedetermination circuit 50 for determining whether or not vehicle code S(vehicle code S=φ_(S)) has been registered in a nonvolatile memory ofthe electronic key 3. The vehicle code determination circuit 50 includesa flag determination circuit, not shown, for determining whether a flagof vehicle code S is set (i.e., whether vehicle code S has been alreadyregistered without φ_(S) being indicated) and a write circuit, notshown, for writing vehicle code S in the nonvolatile memory. The vehiclecode determination circuit 50 is connected to the above-describedvehicle code shift register 32 and also to the nonvolatile memory.

Meanwhile, although in FIG. 3 the transmit-receive controlling circuit 6of the electronic key 3 is shown in a functional block diagram, thetransmit-receive controlling circuit 6 is mainly formed of amicrocomputer.

FIG. 4 is a diagrammatic view showing the overall structure andoperation. In this figure, a vehicle can be provided with at most threeelectronic keys, A, B, and C, including a preliminary key. Separate keycodes each serving as an identification code for specifying a properelectronic key are set for these electronic keys A, B, and C and anidentical vehicle code can be registered in each of these electronickeys.

Namely, key codes K1, K2, and K3 are set for electronic keys A, B, andC, respectively. Further, identical vehicle code S1 can be registered ineach of electronic keys A, B, and C.

On the other hand, three key codes at most can be registered in thevehicle. Namely, key codes K1, K2, and K3 can be registered so as tocorrespond to the three electronic keys A, B, and C, respectively.Meanwhile, key-code setting for the electronic key 3 and vehicle-codesetting for the start-up permission ECU 1 can be effected in such amanner that, for example, these codes are electronically written in by apredetermined write device. Further, registration of the vehicle code inthe electronic key 3 and registration of the key code in the start-uppermission ECU 1 can be effected in accordance with a predeterminedprocedure, which will be described later.

Next, an operation of the above-described structure will be described.

When the electronic key 3 is inserted in the ignition switch 4, thestart-up permission ECU 1 applies a high-frequency electric power to thecoil 2. As a result, induced electromotive force is generated in thecoil 5 of the electronic key 3, and therefore, electric power issupplied for the transmit-receive controlling circuit 6, and inaccordance with the supply of electric power, the transmit-receivecontrolling circuit 6 starts operating.

FIG. 5 shows operation of the start-up permission ECU 1 and FIG. 6 showsthe operation of the transmit-receive controlling circuit 6 of theelectronic key 3. The start-up permission ECU 1 is first set in awaiting state until the ACC signal is input from the ignition switch 4(step S1 of FIG. 5).

When a driver effects a turning operation of the electronic key 3 to theACC position so as to start up the engine, the start-up permission ECU 1generates a random number code (step S2). In this case, the start-uppermission ECU 1 is provided to generate random number code Rn in anupdated state each time the ACC signal is input (operation 1 shown inFIG. 4). At this time, an calculation expression for preparing randomnumber code Rn is set to be different for each type of vehicle or foreach of vehicles for the reason that the random number prepared by apredetermined calculation expression has period characteristics and byunderstanding the period characteristics, decoding of the random numbercode becomes relatively facilitated.

Subsequently, the start-up permission ECU 1 transmits the generatedrandom number code (step S3). As a result, the random number Rn istransmitted from the coil 2 of the start-up permission ECU 1 (see FIG.4).

In this state, the start-up permission ECU 1 is set in a waiting stateuntil it receives the received signal from the electronic key 3 (stepS4).

On the other hand, the transmit-receive controlling circuit 6 of theelectronic key 3 is set in a waiting state until it receives thereceived signal from the start-up permission ECU 1 (step T1 in FIG. 6),and determines whether random number code Rn has been received or not atthe point in time when the received signal was received (step T6). Whenit is determined that random number code Rn has been received, thetransmit-receive controlling circuit 6 receives random number code Rnindicated by the received signal (step T2).

Subsequently, the transmit-receive controlling circuit 5 reads the keycode and the vehicle code from the nonvolatile memory (step T3),generates the return code on the basis of the key code and the vehiclecode (step T4), and transmits the return code (step T5).

In other words, the transmit-receive controlling circuit 6 prepares thereturn code, Q, by effecting predetermined encryption processing for akey code, K1, which is previously stored on the basis of received randomnumber code Rn and a previously stored vehicle code, S1. Concretely, thetransmit-receive controlling circuit 6 prepares return code Q by usingkey code K1 and vehicle code S1 on the basis of random number code Rnreceived with electric power being supplied by the coil 4 and inaccordance with a predetermined encryption calculation expression,Q=f(R, K, S) (see FIG. 4), and transmits the same through the coil 5.Meanwhile, when the key code of the electronic key 3 has not beenregistered, encryption calculation expression Q is set to be equal tof(R, φ_(K), S) according to φ_(K) which indicates that key code K isblank, which will be described later.

After the start-up permission ECU 1 has received the random number codeas described above, it is brought into a state of receiving the receivedsignal (step S4 in FIG. 5), receives return code Q indicated by thereceived signal when the received signal is received (step S5 andoperation 2 in FIG. 4), and determines whether or not vehicle code S isblank (φ_(S)) (step S13 and the code restoring circuit 19 shown in FIG.2). Since the vehicle code has already been registered unless it isblank (φ_(S)), the start-up permission ECU 1 reads the vehicle code fromthe nonvolatile memory (step S6) and decodes a random number code and akey code from the nonvolatile memory on the basis of the vehicle code(step S7).

Subsequently, the start-up permission ECU 1 reads the random number codefrom the nonvolatile memory (step S8) and determines whether the tworandom number codes coincide with each other (step S9). At this time,when the two random number codes are different from each other, it isdetermined that communication between the electronic key 3 and thestart-up permission ECU 1 is incorrect and the routine proceeds to stepS2, in which communication therebetween is executed again.

Further, when the two random number codes coincide with each other, thestart-up permission ECU 1 makes a determination that communication withthe electronic key 3 is normal, reads a key code from the nonvolatilememory (step S10), and determines whether these two key codes coincidewith each other (step S11). At this time, when the read key codecoincides with any one of the three types of key codes, K1, K2, and K3,previously registered (operation 4 in FIG. 4), the start-up permissionECU 1 outputs the start-up permission signal to the engine-controllingECU 7.

Accordingly, when the engine-controlling ECU 7 inputs the START signalfrom the ignition switch 4 with the start-up permission signal beinginput from the start-up permission ECU 1, the engine-controlling ECU 7drives a starter to start up the engine.

On the other hand, when it is determined in step S13 that vehicle code Sis blank (φ_(S)), in step S20, the key code registering processing shownin FIG. 7 is executed. First, in step S21, on the basis of thedetermination made about whether all of the flags of storage areas A, B,and C (see FIG. 4) of the key codes of the nonvolatile memory of thestart-up permission ECU 1 are set, it is determined whether key codesK1, K2, and K3 have already been registered in all of storage areas A,B, and C of the key codes of the nonvolatile memory of the start-uppermission ECU 1 (a flag determination circuit, not shown, of the keycode collating circuit 24 shown in FIG. 2).

When the decision of step S20 is yes, the three key codes have alreadybeen registered and further key codes cannot be stored, and therefore,the routine returns to step S20 and the routine of the start-uppermission ECU 1 ends. Further, when the decision of step S20 is no, inthe next step S22, key code K is decoded from return code Q (the keycode shift register 22 and the key code collating circuit 24 shown inFIG. 2). In subsequent step S23, key code K is stored in the nonvolatilememory of ECU 1 (a write circuit, not shown, of the key code collatingcircuit 24 shown in FIG. 2), and in step S24, the flag is set.Meanwhile, the writing (registering) processing of key code K iseffected in the order of A, B, and C and the flags are respectively setin this order. As a result, the registering processing of key code K ofthe electronic key 3 in the start-up permission ECU 1 is completed.

In subsequent step S25, random number vehicle code P is transmitted tothe electronic key 3, a subroutine of the key code registeringprocessing ends, and the routine returns to step S20, and as a result,the routine of the start-up permission ECU 1 ends. Note that randomnumber vehicle code P is a code represented by the encryptioncalculation expression P=f(R, φ_(K), S); specifically, R indicates arandom number code represented by Rn as shown in FIG. 4, φ_(K) indicatesthat key code K of the electronic key 3 is not registered (i.e., blank)in the start-up permission ECU 1, and S indicates the vehicle code asdescribed above, concretely, S1. This calculation processing is effectedin the P calculation circuit 40 shown in FIG. 2. As a result, themodulation circuit 10 sends a modulated wave according to theabove-described encryption calculation expression, P=f(R, φ_(K), S), tothe output circuit 12.

When random number vehicle code P is transmitted to the electronic key3, the electronic key 3 is different from random number code Rn in stepT6 shown in FIG. 6, and therefore, the decision of step T6 is no. Instep T10, the vehicle code registering processing shown in FIG. 8 isexecuted.

First, in step T11, it is determined whether random number vehicle codeP (i.e., the code on the basis of the above-described encryptioncalculation expression P=f(R, φ_(K), S)) exists or not. When thedecision of step T11 is no, it is determined that an incorrect signalsuch as a noise signal or the like has been received and the routinereturns to step T10. When the decision of step T11 is yes, in subsequentstep T12, random number vehicle code P is received. In the next stepT13, on the basis of the determination made about whether the flag ofthe storage area S (see FIG. 4) of the vehicle code of the nonvolatilememory of the electronic key 3 is set, it is determined whether vehiclecode S has already been registered in the nonvolatile memory of theelectronic key 3 (a flag determination circuit, not shown, of thevehicle code determination circuit 50 shown in FIG. 3). When thedecision of step T13 is yes, the routine returns to step T10. When thedecision of step T13 is no, in the next step T14, the vehicle code S1 isdecoded from random number vehicle code P (the avehicle code shiftregister 32 and the vehicle code determination circuit 50 shown in FIG.3). In subsequent step T15, vehicle code S1 is stored in the nonvolatilememory of the electronic key 3 (a write circuit, not shown, of thevehicle code determination circuit 50 shown in FIG. 3). In the next stepT16, the flag of vehicle code S is set up so as to avoid the overlappingof registration, and thereafter, the process returns to step T10 and theroutine of the electronic key 3 ends.

In accordance with the above-described structure, the start-uppermission ECU 1 transmits the random number code to the electronic key3, the electronic key 3 generates and transmits the return code by theencryption processing of a key code on the basis of the random numbercode received from the start-up permission ECU 1 and thepreviously-stored vehicle code, the start-up permission ECU 1 decodes,on the basis of the vehicle code, the return code received from theelectronic key 3 to the random number code and the key code, and onlywhen the key code coincides with a previously-registered key code, itoutputs the start-up permission signal to the engine-controlling ECU 7.Accordingly, unlike a conventional structure in which an identificationcode itself is returned from the electronic key, the key code serving asthe identification code stored in the electronic key 3 can further bekept secret.

Further, when the return code is prepared in the electronic key 3, thereturn code is prepared on the basis of the previously registeredvehicle code in addition to the random number code received from thestart-up permission ECU 1. For this reason, the confidentiality of thekey code stored in the electronic key 3 can be further improved.

Moreover, the start-up permission ECU 1 is provided to transmit therandom number code in an updated state each time, and therefore, therandom number code and the return code are each provided to be differenteach time. Accordingly, as compared to a structure in which theidentical random number codes are continuously transmitted, theconfidentiality of the key code can be further improved.

In addition, the calculation expression used to prepare the randomnumber code for each type of vehicle or for each of vehicles is setdifferently, and therefore, the confidentiality of the key code can befurther improved.

The present invention is not limited to the above-described embodiment,and various modifications or extension as described below may be made.

Only the key code or vehicle code may be stored in the transmit-receivecontrolling circuit 6 of the electronic key 3.

The electronic key 3 may also be constructed such that with nomechanical key being used and with only the transmit-receive controllingcircuit 6 being provided therein, the ignition switch 4 may be operatedby other operating means.

The communication between the start-up permission ECU 1 and thetransmit-receive controlling circuit 6 of the electronic key 3 may beeffected in an optical manner.

When the electronic key 3 is inserted in the ignition switch 4, thestart-up permission ECU 1 may transmit the random number code to theelectronic key 3 so as to determine whether the electronic key is trueor false.

In the above-described embodiment, in step S13, it is determined fromreturn code Q whether vehicle code S is blank (φ_(S)). However, in placeof the decision made in step S13, the determination may be made aboutwhether key code K has been registered in the nonvolatile memory of thestart-up permission ECU 1 after step S1. Further, in this case, althoughthe determination is made about whether the random number code exists ornot in step T6, a determination may be made about whether vehicle code Kis stored in the electronic key 3.

Further, in the above-described embodiment, after the registration ofkey code K in the nonvolatile memory of the start-up permission ECU 1,vehicle code S is registered in the nonvolatile memory of the electronickey 3. However, random number code Rn and random number vehicle code Pare transmitted from the start-up permission ECU 1, and thedetermination is made about whether or not vehicle code S is stored inthe electronic key 3. When vehicle code S is not stored and if vehiclecode S is decoded, vehicle code S can be previously registered in theelectronic key 3. In addition, in this case, so long as random numbercode Rn is not transmitted from the start-up permission ECU 1 and randomnumber vehicle code P is first transmitted, it is possible to reduce thetime for transmission of random number code Rn, and therefore, the timefor registration can also be reduced.

INDUSTRIAL AVAILABILITY

As described above, the vehicle start-up permission device and theidentification code registering method according to the presentinvention allow the identification code to be kept secret, andtherefore, the present invention is effective in that a vehicle isexclusively possessed by a proper possessor, and the identification coderegistering method allows the vehicle start-up permission device and atransmitter to be separately managed until both identification codes areregistered. Accordingly, in the automobile industry with the division ofa manufacturing process being advanced, the present invention is alsoeffective in that the management aspect in production and marketing ofvehicles is alleviated.

We claim:
 1. An identification code registering method comprising:(A)registering a transmitter-receiver code in a transmitter-receiver, thetransmitter-receiver code specifying a transmitter-receiver, and avehicle code in a vehicle start-up permission device, the vehicle codespecifying a vehicle; (B) transmitting a random number code prepared onthe basis of a predetermined procedure in the vehicle start-uppermission device to the transmitter-receiver,converting bypredetermined encryption processing the transmitter-receiver code to areturn code on the basis of the random number code received by thetransmitter-receiver, transmitting the return code to the vehiclestart-up permission device, restoring the return code received by thevehicle start-up permission device to the transmitter-receiver code onthe basis of the transmitted random number code, and registering thetransmitter-receiver code in the vehicle start-up permission device; and(C) converting by predetermined encryption processing the vehicle codeto a random number vehicle code on the basis of the random numbercode,transmitting the random number vehicle code to thetransmitter-receiver, restoring the random number vehicle code receivedby the transmitter-receiver to the vehicle code on the basis of therandom number code, and registering the vehicle code in thetransmitter-receiver; wherein:the transmitter-receiver prepares to asecond return code based on a second random number code received by thetransmitter-receiver and the transmitter-receiver and vehicle codesregistered in the transmitter-receiver; the vehicle start-up permissiondevice decodes the second return code to obtain at least thetransmitter-receiver code using at least the vehicle code registered inthe vehicle start-up permission device; and the vehicle start-uppermission device permits start-up of an engine only when thetransmitter-receiver code subsequently obtained from the transmitterreceiver coincides with the transmitter-receiver code stored in thevehicle start-up permission device.
 2. An identification coderegistering method according to claim 1, further comprising, when atleast one portion of the transmitter-receiver is determined to beacceptable by the vehicle start-up permission device, executing step(B).
 3. An identification code registering method according to claim 2,wherein the transmitter-receiver is a vehicle electronic key, and whenthe vehicle electronic key is inserted into and turned to apredetermined position of an ignition switch, determining whether the atleast one portion of the transmitter-receiver is acceptable by thevehicle start-up permission device.
 4. An identification coderegistering method according to claim 1, wherein step (B) is executedwhen the transmitter-receiver code of the transmitter-receiver is notregistered in the vehicle start-up permission device.
 5. Anidentification code registering method according to claim 1, whereinstep (C) is executed when the vehicle code has not yet been registeredin the transmitter-receiver.
 6. An identification code registeringmethod according to claim 1, wherein the random number code transmittedby the vehicle start-up permission device in step (B) includesinformation regarding whether the transmitter-receiver code of thetransmitter-receiver has been registered in the vehicle start-uppermission device.
 7. An identification code registering methodaccording to claim 1, wherein the return code transmitted by thetransmitter-receiver in step (B) includes at least one of informationabout that the vehicle code having been registered in thetransmitter-receiver and information about that the vehicle code nothaving been registered.
 8. An identification code registering methodaccording to claim 1, wherein the random number code is prepared in anupdated state every time.
 9. An identification code registering methodaccording to claim 8, wherein the random number code is prepared in adifferent manner for each of a plurality of vehicle types or for each ofa plurality of vehicles.
 10. An identification code registering methodcomprising:(A) registering a transmitter-receiver code in atransmitter-receiver, the transmitter-receiver code specifying atransmitter receiver, and a vehicle code in a vehicle start-uppermission device; (B) converting by predetermined encryption processingthe vehicle code to a random number vehicle code on the basis of arandom number code prepared by a predetermined procedure in the vehiclestart-up permission device,transmitting the random number vehicle codeto the transmitter-receiver, restoring the random number vehicle codereceived by the transmitter-receiver to the vehicle code on the basis ofthe random number vehicle code received by the transmitter-receiver, andregistering the vehicle code in the transmitter-receiver; and (C)transmitting the random number code to thetransmitter-receiver,converting by predetermined encryption processingthe transmitter-receiver code to a return code on the basis of therandom number code received by the transmitter-receiver, transmittingthe return code to the vehicle start-up permission device, restoring thereturn code received by the vehicle start-up permission device to thetransmitter-receiver code on the basis of the random number code, andregistering the transmitter-receiver code in the vehicle start-uppermission device; wherein:the transmitter-receiver converts thetransmitter-receiver code to the return code based on the random numbercode received by the transmitter-receiver and the vehicle coderegistered in the transmitter-receiver; the vehicle start-up permissiondevice decodes the return code to obtain at least thetransmitter-receiver code using at least the vehicle code registered inthe vehicle start-up permission device; and the vehicle start-uppermission device permits start-up of an engine only when thetransmitter-receiver code subsequently obtained from the transmitterreceiver coincides with the transmitter-receiver code stored in thevehicle start-up permission device.
 11. An identification coderegistering method according to claim 10, further comprising when atleast one portion of the transmitter-receiver is determined to beacceptable by the vehicle start-up permission device, executing step(B).
 12. An identification code registering method according to claim11, wherein the transmitter-receiver is a vehicle electronic key, andwhen the vehicle electronic key is inserted into and turned to apredetermined position of an ignition switch, determining whether the atleast one portion of the transmitter-receiver is acceptable by thevehicle start-up permission device.
 13. An identification coderegistering method according to claim 10, wherein step (C) is executedwhen the vehicle code has not yet been registered in thetransmitter-receiver.
 14. An identification code registering methodaccording to claim 10, wherein step (C) is executed when thetransmitter-receiver code of the transmitter-receiver is not registeredin the vehicle start-up permission device.
 15. An identification coderegistering method according to claim 10, wherein the random number codetransmitted by the vehicle start-up permission device in step (B)includes information regarding whether the transmitter-receiver code ofthe transmitter-receiver has been registered in the vehicle start-uppermission device.
 16. An identification code registering methodaccording to claim 10, wherein the return code transmitted by thetransmitter-receiver in step (C) includes information regarding whetherthe vehicle code has been registered in the transmitter-receiver.
 17. Anidentification code registering method according to claim 10, whereinthe random number code is prepared in an updated state every time. 18.An identification code registering method according to claim 17, whereinthe random number code is prepared in a different manner for each of aplurality of vehicle types or for each of a plurality of vehicles.